She travelled the globe to re-discover the lost stories of the world's most famous spices. Here, Kate Humble talks to Wanderlust about her journey

Daisy Cropper: How did the series come about?

Kate Humble: The series, The Spice Trail, came about for two reasons: one is that I had presented a series, which focused on an amazing route through the Middle East called the frankincense trail. Four or five years later somebody at the BBC said, “Oh I really like that!” Or at least the sound of that journey and it went from there.

I did The Frankincense Trail and it seems that people, or the audience, were interested in the old routes and the history behind them. I suppose people in this country don’t really use frankincense, but it is still used and it is something that everyone recognises and I think they (the audience) liked the story behind that.

And so after The Frankincense Trail, other people started thinking about more ideas and a guy called Richard Shaw, who works at Lion Productions, the company that made this programme, had always been a real foodie and had always been interested in spices and had done quite a lot of these spice journeys. He asked me whether it would be interesting to do a series based around the journeys that were inspired by looking for spices and I said, “I can’t think of anything better!”

I’m really into spicy foods and I use spices a lot and it was one of those ideas that the more you looked into the concept, the more multi-layered you realised it was, so it wasn’t just about these spices but what they actually inspired people to do, which was to take incredible, pioneering journeys. I mean spices actually made Europeans discover the world.

DC: So why do you think Europeans followed these spices?

KH: Well it was greed really, a mercenary greed rather than foodie greed, as they wanted to be able to control the spice trade because spices were hugely expensive and the reason they were so expensive was that no one knew their origin. The spices would come into Europe via a caravan of traders, by boat or overland. People in Europe realised if they could find out where these spices came from and control the whole trade right from shore to sail they would become very rich and powerful.

So that was their primary reason for setting off and literally sailing off to what was the unknown world for Europeans at that time. We’re talking the 15th Century, the European map then was the Mediterranean and North Africa they didn’t even know India existed. So they were literally stepping off into their boats and sailing off their known map.

DC: Aside from foods and spice themes, what can viewers hope to learn from the series?

KH: Well I think one of the things I certainly found fascinating was that all the spices we look at (we look at six spices altogether: pepper, cinnamon, cloves, nutmeg, vanilla and saffron) they’re all, with the exception of saffron, used quite frequently. Pepper we use every day, and yet what I found amazing was how little I knew about these spices and I’m guessing that I’m not alone in that.

We all have these funny little jars in our kitchens, with these wonderfully exotic things in them but I’d never seen cinnamon growing. I had no idea how cinnamon went from plant to cinnamon sticks you buy in the jar. I had no idea that vanilla actually originates in Mexico not in Madagascar which is where a lot of us think it comes from and that’s something which is held up as a great culinary treat: Madagascan vanilla.

There’s the botany of the spices: how they grow, how they were then transferred to other parts of the world, I think it’s fascinating.

And then of course we went to some amazing countries and looked at the modern day uses of the spices and how they are very intrinsic to modern day culture just as much as in the middle ages. I think it’s a really fascinating blend of history, of travel and of culture.

DC: Do you think viewers will be surprised at how much effort goes into the different processes needed to produce spices?

KH: I think they will be quite shocked at how labour intensive these spices are. You don’t just pick them and put them in a jar; there’s a lot of preparation that goes into them. We always talk about saffron or good vanilla being really expensive but when you learn about the whole process that goes into creating these really exotic flavours, from the other side of the world, it’ll make people think and look at the fair trade side of this.

We look at fair trade as a great success, when we’re buying bananas, chocolate, sugar or coffee, for example, but I don’t think any of us has really thought about fair trade as far as spices are concerned, but we should.

I met farmers that were being offered a price for their amazing products, for their beautiful, organic cinnamon that had take many man hours just to prepare it for the market and the farmer was being offered 2,000 times less than we would pay for a much lesser product in the supermarkets here, so I think people will be surprised at just how labour intensive and skilled and how much skill is needed to produce these spices that we totally take for granted now.

DC: So you earlier admitted to being a foodie, did you get to experience much local cooking while you were filming?

KH: The one spice that we featured and I’ve never like is vanilla so I had to confess, that I’ve never really liked vanilla and we were working with a top chef in Mexico city and he was of course horrified when I admitted that I hated vanilla. And he said, “OK I’m going to make you something that will change your mind,” and I was really sceptical and thought, “It’s not going to work!”

I think the reason I don’t like vanilla is that it tends to be mixed with very sweet things or very creamy foods and I don’t like either of those but the chef used it in an amazing savoury, meat stew and it was incredible. The vanilla gave a real roundness and interesting flavour not what you would think of, or what I would think of as that really sickly vanilla flavour at all. So I had to walk out with my tail between my legs and the chef was looking very pleased with himself.

I didn’t actually cook with cinnamon on the farm we visited in Sri Lanka, but I learnt how to peel it and prepare it and roll it. I was completely rubbish at it obviously, but I had real hands on experience on how cinnamon is produced and then the farmer uses it to make tea and he literally uses a few flakes of cinnamon from a cinnamon stick with hot water and brown sugar and its the most delicious really refreshing tea particularly when its boiling hot, so that a nice tip.

Saffron is another amazing spice; it comes from a crocus. This time of year some of us will see crocuses come up in our gardens and a saffron crocus looks exactly the same but the one difference is that they have these bright orangey red stigma, they almost look like feelers, that come out of the middle of the plant. Saffron is enormously expensive and my goodness I found out why: every crocus flower has to be picked by hand and every stigma has to be removed by hand. There’s no way, or at least no way I can see how to mechanise it at all.

So a kilo of saffron takes 200,000 flowers and costs £4,000, but what’s surprising is we always use saffron in tiny amounts; because its so expensive. I’ve never really appreciated the taste of it before. I didn’t really know what it tasted of, it’s something we use to give rice a bit of colour or something like that but in Morocco and Spain, where we filmed saffron’s story, they are very proud of their saffron traditions and they use it generously. It’s got the most indescribable smell: a mixture of honey and musk. You can’t describe it as sweet or bitter, its just one of those smells and the taste is just as incredible and what I am guilty of, is having saffron in a jar for years and its gone well past the sell by date, but tasting it almost fresh is a completely different experience.

DC: Did you have a favourite spice? Or a spice that brought back memories of your childhood?

KH: I think pepper in a way as none of us give pepper a second thought; every table in the country has a peppershaker or grinder and yet the story behind it is so extraordinary. It was so expensive in the 14th Century that it was known as black gold. When the ships came into the ports in London the people that worked in the docs weren’t allowed pockets or cuffs because if they stole a handful of pepper it could keep them in a grand style for the rest of their lives.

I discovered another thing about pepper, which makes me laugh every time I use it. Pepper grows on what’s called a spike, it’s almost like a miniature bunch of grapes. It has green berries that grow on a spike and the spikes are picked and the berries removed, and then they’re dried in the sun and that’s what gives them the black colour and the heat.

The berries are removed from the spikes by being danced on. So people take their shoes off and dance on the pile of pepper spikes so the berries are separated off from the storks, it just made me wonder whether that contact with bare feet right at the start is what really gives pepper its flavour.

DC: Was there a spice you enjoyed tracing the most?

KH: Again, I would say pepper. It’s one that we really don’t ever think about and its was just such a surprise to see it growing and how it ends up being the pepper which is so familiar to us.

Having said that to find nutmeg and cloves on their home island, they’re extraordinary. Nutmeg in the 15th Century only grew on six islands within the country of Indonesia.

Indonesia has 17,500 islands and only six islands had nutmeg on, so how anyone ever found them is astonishing. Nutmeg is still very much part of the culture on the islands. People treat their nutmeg trees like a bank account so when people are short of money they will go and harvest some nutmeg and sell it in the market.

They are very beautiful fruits: the nutmeg kernel is actually the full thing. You’ve got the fruit which looks almost like a golden plum, and then there’s a fleshy fruity bit which the local’s use to make a sort of jam or candy and under that there’s this amazing bright red, looks like almost like a bright red net around the kernel in the middle of the fruit and that s mace, again another hugely expensive and sought after spice. In its fresh state the surrounding net is an absolutely vivid red.

When you crack open the nutmeg fruit you get this real shock because there’s this bright red underneath it and you carefully peel the mace net away from the kernel and then you’ve got this kind of shiny kernel and you think oh that’s the nutmeg but it’s not. You’ve then got to crack off this surrounding brittle shell, and underneath is the nutmeg. The nutmeg that everyone went mad for in the 14th and 15th Century and which people thought could cure the plague, so again it’s another amazing spice to see in a natural form.

DC: What advice or tips would you give to travellers who want to buy spices locally?

KH: I would say if it’s at all possible to try and find farmers. The farmer I worked with in Sri Lanka with cinnamon asked me, “Do you think people would be interest in seeing my farm?”

I said absolutely; because for us, we don’t know what cinnamon looks like and I think most people would find it fascinating.

Similarly if anyone did get to the Banda islands in Indonesia every family will have nutmeg trees and they will happily, proudly show you their trees. If you buy it directly from the people that grow it, they see the proper benefit of their work. I think that it is harder work for us but your readers are super intrepid and are not to be put off by having to search for what they are looking for.

So that’s my best tip: find the person who grows it. In Mexico with vanilla, for example, we went to the biggest market in Mexico City and you couldn’t find vanilla anywhere because the locals simply don’t use it.

Some vanilla comes a town called Papantla, if travellers find themselves there they will see Posnac women walking along with handfuls of vanilla pods – well that’s who to buy if from because they really know what they’re talking about. It ‘s about trying to cut out as many middle men and other sellers as possible to get to the source of the spice, because first of all it will be wonderful and you’ll actually be rewarding the people who do all the hard work and thirdly you’ll learn so much more about that spice and everybody I met along the way were so pleased and proud of what they do and to share their knowledge.

DC: Now you’re back in the UK, do you incorporate cooking techniques you learnt along the way?

KH: What I did almost immediately when I got back home was to look at the sell by dates on my spice jars and chuck out a load of horrible, dusty spices that had been there far too long. Now I am much more conscious of using fresh spices and I know how to use them properly; my husband has got really into cooking too and made me a delicious curry last night.

It was a journey that will have lots of long-term culinary effects for me.

DC: Earlier you mentioned that The Spice Trail, was a spin-off from your earlier series, The Frankincense Trail, do you think there will be more series on the same subject in the future?

KH: I hope so! I think trade is the thing that really opens up the world and really allows human beings to explore and travel and unfortunately, to behave extremely badly a lot of the time as well. But there are a lot of commodities that have opened up the world to us and continue to open up the world to us. I don’t know what might be next but it would be lovely to think that there is another part of the world that can be explored and celebrated through its natural resources.

DC: Onto Stuff your Rucksack: Did you take anything on your travels?

KH: I didn’t actually and the main reason was that we were going to quite remote places. I always looked it up to find out whether there was anything that we could take to these places and unfortunately there wasn’t. The other downside was that as soon as we hit the ground we were working flat out all the time.

However, when we finished filming The Spice Trail I had ten days off in the beginning of December. My husband and I went to Kenya and we said we must try to ‘stuff our rucksacks’ so we looked up to see what there was in Kenya. We were going to be in Nairobi for one night and we saw that there was an SOS Village just outside Nairobi. They needed pencils and pens and colouring books, slightly educational stuff but for kids to play with and we contacted them and said we’re coming and could we come and visit.

It was just fantastic! It was fantastic to do it, it was fantastic to see how this organisation worked and it was great to see the need for the stuff we’d taken and getting an immediate reaction from the moment we gave the stuff over.

It was an amazing feeling to actually see this little idea I had four or fives years ago, with thanks to all the people who’ve helped and everybody whose been involved in it, to actually see it works and it really is a rewarding thing to do. It was one of the highlights of our whole Kenyan trip.